Question

我有一个显示日期的UILabel和一个可以更改UILabel中日期的UIDatePicker。如何在故事板中更改视图时“保存”所选日期，因此当我使用UILabel返回视图时，选择的日期仍然保存而不是恢复到今天的日期？以下是显示NSDate的UIDatePicker和UILabel的代码：

- (void)flatDatePicker:(FlatDatePicker*)datePicker dateDidChange:(NSDate*)date {

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
NSCalendar *coptic = [[NSCalendar alloc] initWithCalendarIdentifier:@"coptic"];
[dateFormatter setCalendar:coptic];
[dateFormatter setDateStyle:NSDateFormatterLongStyle];

if (datePicker.datePickerMode == FlatDatePickerModeDate) {
    [dateFormatter setDateFormat:@"EEEE, MMMM, dd, yyyy"];
} else if (datePicker.datePickerMode == FlatDatePickerModeDate) {
    [dateFormatter setDateFormat:@"HH:mm:ss"];
} else {
    [dateFormatter setDateFormat:@"EEEE, MMMM, dd, yyyy HH:mm:ss"];
}
NSString *value = [dateFormatter stringFromDate:date];
self.labelDateSelected.text = value;
}

Answer 1

您可以将NSDate存储在变量中。然后在viewWillDisappear中保存日期：

-(void)viewWillDisappear:(BOOL)animated {
     NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
     [defaults setObject:lastPickedDate forKey:@"lastDate"];
}

然后，当您返回此屏幕时，您可以验证是否保存了日期并在viewDidLoad或viewDidAppear中恢复它。

-(void)viewDidLoad {
     //another code

     NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
     NSDate *date = [defaults objectForKey:@"lastDate"];

     if(date) {
        _datePicker.date = date;
     }
}

在StoryBoard - iOS中更改视图时保存NSDate数据

1 个答案: